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Native Plant Trust: Go Botany Discover thousands of New England plants

Persicaria setacea — bristly smartweed

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Facts

Bristly smartweed is a rare plant of pond shores, streams and marshes along the coastal plain in Massachusetts and Rhode Island. A population was also recorded from Hampden County, Massachusetts, inland and disjunct from the others, but is no longer thought to exist. This semi-aquatic, perennial plant needs periodic flooding to eliminate competing plants, and its uncommon habitats are vulnerable to drought and trampling. Its greenish-white flowers (produced in July to mid-September) and hairy-bristly ochrea (a cylindrical sptipule wrapping the stem at the leaf nodes) distinguish it from the more common P. hydropiperoides, with which it sometimes co-occurs.

Habitat

Marshes, shores of rivers or lakes

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
  • aquatic
  • wetlands
New England state
  • Massachusetts
  • Rhode Island
Flower petal color
  • green to brown
  • white
Leaf type
the leaves are simple (lobed or unlobed but not separated into leaflets)
Leaf arrangement
alternate: there is one leaf per node along the stem
Leaf blade edges
the edge of the leaf blade is entire (has no teeth or lobes)
Flower symmetry
there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
Number of sepals, petals or tepals
there are five petals, sepals, or tepals in the flower
Fusion of sepals and petals
the petals or the sepals are fused into a cup or tube
Stamen number
5
Fruit type (general)
the fruit is dry but does not split open when ripe
Fruit length
1.5–2.5 mm
Show all characteristics

  • Clonal plantlets

    Bulbils
    the plant does not appear to have bulbils
    Bulblets replace flowers
    there are no bulblets where the flowers are located

  • Flowers

    Anther opening
    the anthers have narrow slits or furrows that run lengthwise along the anthers
    Anther spurs
    the anthers do not have spurs on them
    Calyx growth after flowering
    the calyx does not grow to cover or partially cover the fruit
    Calyx symmetry
    there are two or more ways to evenly divide the calyx (the calyx is radially symmetrical)
    Carpels fused
    the carpels are fused to one another
    Corolla palate
    no
    Corona lobe length
    0 mm
    Epicalyx
    the flower does not have an epicalyx
    Epicalyx number of parts
    0
    Filament surface
    the filament is smooth, with no hairs or scales
    Flower description
    the flower has a superior ovary, and lacks a hypanthium
    Flower petal color
    • green to brown
    • white
    Flower reproductive parts
    • the flower has both pollen- and seed-producing parts
    • the flower has either only pollen- or only seed-producing parts
    Flower symmetry
    there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
    Flowers sunken into stem
    no
    Form of style
    the style is branched above the base
    Fusion of sepals and petals
    the petals or the sepals are fused into a cup or tube
    Horns in hoods (Asclepias)
    NA
    Hypanthium
    • the flower does not have a hypanthium
    • the flower has a hypanthium
    Inflorescence length
    20–80 mm
    Inflorescence one-sided
    the flowers are arrayed in a spiral around the inflorescence axis or branches, or occur singly, or in several ranks
    Inflorescence width
    4–8 mm
    Inner tepals (Rumex)
    NA
    Nectar spur
    the flower has no nectar spurs
    Number of carpels
    2–3
    Number of pistils
    1
    Number of sepals, petals or tepals
    there are five petals, sepals, or tepals in the flower
    Number of styles
    1–3
    Ovary position
    the ovary is above the point of petal and/or sepal attachment
    Perianth shape
    • the perianth is campanulate (bell-shaped, with a tube about as long as wide, flaring at the mouth)
    • the perianth is cupuliform (cup-shaped)
    Petal and sepal arrangement
    the flower includes two cycles of petal- or sepal-like structures
    Petal and sepal colors
    • green to brown
    • white
    Petal appearance
    • the petals are green and/or leafy in texture
    • the petals are thin and delicate, and pigmented (colored other than green or brown)
    Petal folds or pleats
    the petals of the flower do not have folds or plaits
    Petal hairs (Viola)
    NA
    Petal tips (Cuscuta)
    NA
    Reproductive system
    all the flowers have both carpels and stamens (synoecious)
    Scales inside corolla
    no
    Sepal and petal color
    the petals and sepals are similar
    Sepal appearance
    the sepals are green or brown, and leaf-like in texture
    Sepal appendages
    the sepals do not have appendages on them
    Sepal appendages (Oenothera)
    NA
    Sepal color
    green to brown
    Sepal number
    5
    Sepals fused only to sepals
    the sepals are fused to each other (not other flower parts), at least near their bases
    Stamen morphology
    the stamens within each cycle are the same
    Stamen number
    5
    Stamen position relative to petals
    NA
    Style petal-like
    the styles are not petal-like
    Umbel flower reproductive parts
    NA
    Upper lip of bilabiate corolla
    NA

  • Fruits or seeds

    Achene relative orientation
    the achenes are perpendicular to the plane of the perianth (vertical)
    Achene shape
    the achenes are another shape in outline
    Achene surface (Polygonum)
    NA
    Achene type
    the fruit is an achene (dry, indehiscent, and usually one-seeded)
    Berry color
    NA
    Capsule color (Viola)
    NA
    Capsule ribs
    NA
    Capsule splitting
    NA
    Fruit (pyxis) dehiscence
    NA
    Fruit features (Brassicaceae)
    NA
    Fruit length
    1.5–2.5 mm
    Fruit locules
    one
    Fruit type (general)
    the fruit is dry but does not split open when ripe
    Fruit type (specific)
    the fruit is an achene (dry, usually one-seeded, does not separate or split open at maturity)
    Legumes (Fabaceae)
    NA
    Mericarp length
    0 mm
    Mericarp segment shape (Desmodium)
    NA
    Other markings on berry
    NA
    Ovary stipe
    the ovary or fruit does not have a stipe
    Placenta arrangement
    the plant has basal placentation, where one or a few ovules develop at the base of a simple or compound ovary
    Rows of seeds in fruit (Brassicaceae)
    NA
    Schizocarpic fruit compression
    NA
    Schizocarpic fruit segments
    0
    Septum in fruit (Brassicaceae)
    NA
    Wings on fruit
    the fruit does not have wings on it
    prickles on fruits
    the fruits do not have thorn-like defensive structures

  • Glands or sap

    Glands on leaf blade
    the leaf blades do not have glandular dots or scales
    Sap
    the sap is clear and watery
    Sap color
    the sap is clear

  • Growth form

    Growth form
    the plant is an herb (it has self-supporting stems)
    Horizontal rooting stem
    • the plant does not have stolons
    • the plant has stolons
    Lifespan
    the plant lives more than two years
    Parasitism
    the plant is not parasitic
    Plant color
    the leaves or young stems of the plant are green
    Plants darken when dry
    no
    Spines on plant
    the plant has no spines
    Underground organs
    the plant has a rhizome (a horizontal underground stem with roots growing from it)

  • Leaves

    Bracteole number (Apiaceae)
    0
    Bracts in plantain (Plantago)
    NA
    Final leaf segment length (compound lvs only)
    0 mm
    Final leaf segment length to width ratio (compound lvs only)
    0
    Hairs on underside of leaf
    the underside of the leaf is fuzzy or hairy
    Hairs on upper side of leaf
    the upper side of the leaf is fuzzy or hairy
    Leaf arrangement
    alternate: there is one leaf per node along the stem
    Leaf blade base
    • the leaf has a distinct leaf stalk (petiole)
    • the leaf has no stalk
    Leaf blade base shape
    • the base of the leaf blade is cuneate (wedge-shaped, tapers to the base with relatively straight, converging edges), or narrow
    • the base of the leaf blade is truncate (ends abruptly in a more or less straight line as though cut off)
    Leaf blade edges
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf blade length
    30–180 mm
    Leaf blade shape
    the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
    Leaf blade surface colors
    the upper side of the leaf blade is relatively uniform in color
    Leaf blade width
    1.5–4.8 mm
    Leaf duration
    the leaves drop off in winter (or they whither but persist on the plant)
    Leaf form
    the leaves are green, with an expanded blade and a leaf-like texture
    Leaf spines
    there are no spines on the leaf edges
    Leaf stalk
    • the leaves have leaf stalks
    • the leaves have no leaf stalks, but attach directly to the stem
    Leaf teeth and lobes
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf type
    the leaves are simple (lobed or unlobed but not separated into leaflets)
    Leaf variation
    the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
    Leaflet number
    0
    Leaves per node
    there is one leaf per node along the stem
    Pinnately compound leaf type
    NA
    Specific leaf type
    the leaves are simple (lobed or unlobed but not separated into leaflets)
    Stipels
    NA
    Stipule features
    • the stipules are hairy with hairs standing out at a 45 to 90 degree angle, or pressed to the stipule surface
    • the stipules are straight (or somewhat slanted) across the top
    • the stipules have a fringe of cilia along the top edge
    Stipule fused to leaf stalk
    the stipules are fused to the petioles for some or most of their length
    Stipule shape
    the stipules are tubular (cylindrical and hollow)
    Stipules
    the plant has stipules

  • Place

    Habitat
    • aquatic
    • wetlands
    New England state
    • Massachusetts
    • Rhode Island
    Specific habitat
    • marshes
    • shores of rivers or lakes

  • Scent

    Plant odor
    the plant does not have much of a smell

  • Stem, shoot, branch

    Branched tendrils
    NA
    Flowering stem cross-section
    the flowering stem is circular, or with lots of small angles so that it is roughly circular
    Hair between stem nodes
    • the stem has hairs between the nodes
    • the stem has no hairs between the nodes
    Hairs between stem nodes
    • the hairs on the stem are plain, without glands or branches, and not tangled
    • the stem has no hairs between the nodes
    Hooked hairs on stem between nodes
    no
    Leaves on stem
    there is at least one full leaf above the base of the flowering stem
    Plant height
    50–150 cm
    Stem hair distribution
    the hairs on the stem are mainly found at the nodes
    Tendril origin
    NA
    Tendrils
    the plant does not have tendrils

Wetland status

Occurs only in wetlands. (Wetland indicator code: OBL)

In New England

Distribution

Connecticut
absent
Maine
absent
Massachusetts
present
New Hampshire
absent
Rhode Island
present
Vermont
absent

Conservation status

Exact status definitions can vary from state to state. For details, please check with your state.

Massachusetts
rare (S-rank: S2), threatened (code: T)
Rhode Island
historical (S-rank: SH), state historical (code: SH)

From Flora Novae Angliae dichotomous key

20.  Persicaria setacea (Baldw.) Small NC

bristly smartweed. Persicaria setacea (Baldw.) Small var. interjecta (Fern.) C.F. Reed; P. setacea (Baldw.) Small var. tonsa (Fern.) C.F. Reed; Polygonum hydropiperoides Michx. var. setaceum (Baldw.) Gleason; P. setaceum Michx. var. interjectum Fern.; P. setaceum Michx. var. tonsum Fern. • MA, RI; primarily on the coastal plain, disjunct in Hamden County, MA. Pond shores, streams, marshes. Our specimens in New England are much closer to Persicaria hydropiperoides than many treatments present (as evidenced by the characters they use in their identification keys).

Native to North America?

Sometimes confused with

Persicaria hydropiper

Family

Polygonaceae

Genus

Persicaria